Introduction

ThingsBoard is an open-source server-side platform that allows you to monitor and control IoT devices.
It is free for both personal and commercial usage and you can deploy it anywhere.
If this is your first experience with the platform we recommend to review
what-is-thingsboard page and getting-started guide.

This sample application will allow you to control GPIO of your Raspberry Pi device using ThingsBoard RPC widgets. We will observe GPIO control using LEDs connected to the pins.
The purpose of this application is to demonstrate ThingsBoard RPC capabilities.

Raspberry Pi will use simple Android Things application that will connect to ThingsBoard server via MQTT and listen to RPC commands.
Current GPIO state and GPIO control widget is visualized using built-in customizable dashboard.

Prerequisites

List of hardware and pinouts

Raspberry Pi - we will use Raspberry Pi 3 Model B but you can use any other model.

11 LEDs with corresponding resistors

13 female-to-male jumper wires

Wiring schema

Since our application will allow us to control the state of all available GPIO pins, we recommend attaching some LEDs to those pins for visibility.
You can use this basic instruction or another one to wire some LEDs.
Below is sample wiring schema used in this tutorial.

Programming the Raspberry Pi

Flashing the Android Things image

First, you need to flash Android Things image to your Raspberry Pi board using this guide.
After finishing this guide make sure that your board has Internet access and accessible via adb tool.

Android Things development environment

Before starting with application introduced in this tutorial you need to prepare development environment to work with Android Things applications.
Follow instructions from the official guide to build and deploy your first Android Things application.

Application source code

Now you should obtain the source code of the GpioControlSample application from ThingsBoard samples GitHub repository.
You can do this by issuing the following git clone command:

git clone https://github.com/thingsboard/samples

Open cloned samples folder and navigate to android-things/GpioControlSample.

Open GpioControlActivity.java file located at app/src/main/java/org/thingsboard/sample/gpiocontrol folder.

You will need to modify THINGSBOARD_HOST constant to match your ThingsBoard server installation IP address or hostname.
Use “demo.thingsboard.io” if you are using live demo server.

The value of ACCESS_TOKEN constant corresponds to sample Raspberry Pi device in pre-provisioned demo data.
If you are using live demo server - get the access token for pre-provisioned “Raspberry Pi Demo Device”.

Running the application

Make sure that your Raspberry device is accessible via adb tool:

adb devices

Navigate to GpioControlSample application folder and deploy application to the device:

Data visualization

In order to simplify this guide, we have included “Raspberry PI GPIO Demo Dashboard” to the demo data that is available in each Thingboard installation.
Of course, you can modify this dashboard: tune, add, delete widgets, etc.
You can access this dashboard by logging in as a tenant administrator.

Once logged in, open Dashboards->Raspberry PI GPIO Demo Dashboard page. You should observe demo dashboard with GPIO control and status panel for your device.
Now you can switch status of GPIOs using control panel. As a result, you will see LEDs status change on the device and on the status panel.

Below is the screenshot of the “Raspberry PI GPIO Demo Dashboard”.

Next steps

Browse other samples or explore guides related to main ThingsBoard features: